Printing plate means



Dec. 31, 1946.

w. c. TOLAND PRINTING PLATE MEANS Filed July 22, 1942 press. I plate holder in which colloid. plates and other this purpose.

latented Dec. 31,

2,413,664 PRINTING PLATE omens William Craig Toland, Broohline, Mass, assignor 'to William Craig Toland, trustee Application uly 22, 1e42, Serial No. assets 3 Claims. toi etreas) This invention relates to'printing and more especially to planog'raphic printing plate means.

An object of the invention'is to improveplanographic printing plates and to devise a composite printing plate member in which metal and other materials are combined with a view to formin a non-stretch flexible printing plate, whichis cheap, easy to handle and sufficiently durable to withstand clamping on a lithographic printing Another object is to provide a printing typeset paper or plastic plates may be detachabiy supported. The invention also aimsto provide improved means of securing paper printing plates to a printing member.

The nature of the invention will be more fully understood from the following description of the drawing and discussion relating thereto.

in the accompanying drawing:

Figure l is a plan view illustrating a plano= graphic printing plate support of the invention;

Fig. 2 is a cross section taken on the line 22 of Fig. l and further illustrating a printing plate element mounted in the support; and

' Fig. 3 is an enlarged fragmentary cross sec;- tional View of a modification of the invention.

The invention generally includes a frame or support constructed of a relatively iiexibleand durable material such as sheet metal, which is adapted to be secured to a lithographic printing press by clamping means commonly employed for The frame or support is formed with an opening extending throughout a part of support 5.

5 are strips l of adhesive material, such as for example Scotch tape.

Surfaces oi the marginal portions 3 are roughened to provide a lithographic grain corresponding to usual grained surfaces of lithographic printing plates. The grained surfaces t are adapted to being etched and treated with aqueous mixtures, thereby to form water-receptivegrease-repellent, ricn prlnting portions of a planographic printing plate.

Mounted in the opening 2 in abutting relation with respect to inner edges of the marginal portions 3 is a paper printing element t, which is preferably of a thickness corresponding to the depth of the opening 2 so that the surface of the printing plate element lies in the same general plane with respect to the grained surface or the The strips E securely hold the element in the base of the support 9, while perthe thickness of the plate, in which is detachably supported a paper or plastic printing plate. The surface of the paper or plastic printing plate occurs flush with the surface of the support or frame, which is grained to constitute non-printing portions adapted to constitute a continuation of non-printing areas of the paper or plastic tends throughout a substantial part of theinner surface of the support i, to leave'outer marginal portions 3.

In a preferred embodiment of the invention, the opening 2 extends throughout a part only of the thickness of the support I, as is better shown in Fig. 2 of the drawing. The opening 2, at either end thereof, is extended to form grooves 5 of slightly increased depth. Located in the grooves mitting it to be lifted away when so desired.

As illustrative of actual dimensions, we may provide a support of zinc or aluminum having a thickness of .015 inch, with the opening 2 having a depth of .006 inch, and with the printing element 6 having a similar thickness of .006 inch.

The printing plate element '8 is preferably formed of paper, plastic or other materials, and includes printing portions 8 and non printing portions 9. The non-printing portions 9 of the printing plate element .8 are arranged to occur in abutting relation with respect to the grained non-printing surfaces i oi the support it so that the grained surfaces ii are a continuation of the non-printing portions 9.

As a result of this arrangement there is provided a composite planographic printing surface, in which the grained metal surface of the support cooperates with the non-printing portions of the printing element to maintain water-receptive ink-repelling character at all points except where printing portions of the printing element 6 occur inside of its marginal edges,

By this means the line ofabutment of the printing element with the support is maintained from intersecting any of the printing images of the printing element and no line in printed subject matter can subsequently appear. The out= line itself does not become transferred since at all points where the margin line occurs both the support and the plate element are water-receptive and hence will repel ink.

A number of advantages are derived from the composite printing structure'relating to the use of paper and plastic materials for the printing element 6. In using paper or plastic printing plates, it is customary to clamp such plates tightly to a roll and this subjects them to stresses which may, in some circumstances, tend also be subject to stretching and shrinking when exposed'to water as it is employed in. lithographic Printing.

It will be seen that possible cracking of the paper plates from being clamped on a roll is substantially reduced or overcome by the composite structure. With respect to the clamping, it is pointed out that the marginal edges of the metal support are available for clamping in the manner common to all metal lithographic plates. The paper plate is directly secured by the adhesive strips which are especially effective due to the recessed arrangement of the paper, plate in the support whereby edges of the paper are snugly fitted against the edges of the plate. With respect to stretching or shrinking, it should be observed that by confining the paper plate in the opening 2 of the support, with the edges of the plate in abutting relation to the edges of the opening 2, there is less opportunity for the paper to become extended. At the same time by atteaching the plate element to the support by means of adhesive strips, i, or by adhesive placed over the entire under surface of the plate element, this member is further prevented from shrinking.

The use of the frame or support 5 eliminates handling of plates in many instances since the support may be clamped on a lithographic print- .ing roll or other type of printing member, and locked in a correct position to carry out a printirig operation. Thereafter paper printing plate elements may be inserted and removed from time to time as required, with considerable savto cause the plates to crack. Such plates may ing of time and labor. It is also pointed out that of themselves adapted to be clamped on printing machines. Various other advantages are present also, such as savings in development 1abor, reduction in the amount of developing mate.- rial used, and the like.

I The support I may be formed in various ways as by forming the opening 2 with a, die, or cutting the opening out, or casting a metal sheet having this general formation. It may be desired to modify the construction of the support, as for exampleby using two supporting plates, one of which is formed with an opening land one of which is not. Still further, it may be desired to provide a support in which the opening is cut all the way therethrough, or the opening may be desired to be directly incorporated in a printing roll or platen in a, lithographic printing machine.

The printing plate element may also be desired to be employed with a printing element such as illustrated in Fig. 3 in which a plate I0 is made up of layers of paper It and resin material l2,'over which is applied a water-receptive coatelement.

, 4 composed of paper having lithographic coatings which may be treated to render them'suitable for lithographic printing. Various other means of fastening the printing element in the support may be desired to be employed. For example, the edges of the printing element may be beveled to fit with correspondingly beveled edges in a modified support, and other changes made use of.

While we have shown a preferred embodiment of our invention, it should be understood that various changes and modifications may be resorted to, in keeping with the spirit of the invention as defined by the appended claims.

We claim:

1. A planographic printing plate comprising in combination; a thin, flexible, support member presenting marginal surface portions adapted to constitute non-printing portions, said surfaces surrounding an opening in spaced relation to the outer edges of the support member, an insert planographic printing plate secured. within the said opening and substantially filling the same with its edges lying in abutting relation to the walls of the opening, said support member providing substantial clamping edges for securing the said planographic printing plate to a printing cylinder.

2. An article of the character described comprising; a thin, flexible, metal planographic plate support, said support being formed with a recess in the plate support surface in spaced relation to the outer edges thereof, said recess being defined by retaining edges, a planographic printing plate element mounted in the said opening with its edges lying in abutting relation with respect to the said retaining edges, said support presenting a marginal portion which is adapted to provide non-printing portions lying in the same plane with the non-printing portions of the said printing plate element, said marginal portion being further adapted to provide clamping edges for securing the support and plate around the drum of a printing cylinder, thereby to substantially remove tension from the printlng element and to cooperate with the said retaining edges of the opening in maintaining dimensional stability in the said printing element.

3. An article of the character described comprising; a thin, flexible, sheet-metal support, said support having marginal grained surface portions adapted to function as non-printing portions of a planographic printing plate, said support having an opening formed therein which extends throughout a part only of the thickness of the support, a planographic printing plate element formed of paper and resinous materials secured in the said opening, said plate element being normally resistant to water, means for securing the planographic printing element within the opening, said plate element presenting printing portions and non-printing portions, said nonprinting. portions being supported in the plane of the grained surface of the said support, and said grained surface providing a clamping margin for securing the support and plate element around a printing cylinder without substantial pull being exerted on the edges of the plate WILLIAM CRAIG TOLAND. 

